Process of and apparatus for heat treatment of metal objects.



c. NAPIER.

PROCESS OF AND APPARATUS FOR HEAT TREATMENT OF METAL ('JBJECTS.

APPLICATION FILED JANJZI. I918.

I Patented M3y14, 1918.

I subject of the King of Great Britain, and resident of Springfield, in the county of pNrTEn STATES PATENT orr o .cmms'mmmn, orsrnmcrmnn. MASSACHUSETTS, assrcnon ".ro NAPIER saw wonxs, mconrona'rnn, or SPRINGFIELD, uns'sacnusnrrs, nconrona'rron or MASSACHUSETTS.

.IPROCESS OF AND APPARATUS FOR HEAT TREATMEfiT OF 1 IE'1AL OBJECTS.

To all whom it may camera: i

Be it known that. I, CHARLES NAPIER, a

Hampden and State of Massachusetts, haveinvented new and useful Improvements in Processes of and Apparatus for Heat Treatment of Metal Objects, of which the following is a specification.

Thisinventio'n relates to the manufacture ofsaw-blades and other elongate metal ob-- jects such as are subjected to heat-treatment for hardening, tempering or like purposes.

In my Letters Patent No. 1,221,576, dated April 3, 1917, I have described and claimed a machine for the continuous treatment of a seriesof such objects, for instance sawblades or the like, byfirst heating and then quenching in a cooling bath, the saw-blades or the like being connected by removable links so that a chain of blades and links is carried through the machine under longitudinal tension, a heating-oven and a cooling bath being'traversedin succession by each member of the chain of saws, the individualsaws being disconnected by falling away from the connecting links after they pass from the delivery rolls of the tension and feeding means forming a part-of my said machine. The saw blades are thus delivered after being hardened and tempered throughout their lengths while under tension, and to an exact and uniform degree, A finishing operation is in practice still required to draw the temper or anneal the per-. forated ends of the saws, as customary, to

prevent breakage at the ends held by the machine which is also adapted to be practised by said machine, or other apparatus having related functions, whereby such elongate objects may be tempered or heattreated uniformly throughout the greater part of their lengths, as before, but which shall also result in producing a product anhealed or softened at one or both of its ends without any second'or separate operation.

Thisinvention also relates to a member of a chain'of objects adapted to be treated by my new method and constituting in connection with heating and cooling means for the chain of objects means. adapted locall to modify the heating and cooling effect 0 the heating and cooling means, so as to permit one part of the object under treatment to be subjected to changes oftemperature different from those permitted at another part.

Principal objects of the invention are therefore .to provide a continuous process for locally tempering and locally annealing each of a series of elongate metal objects, and to provide amember adapted to join such objects in a chain which shall be adapted locall to modifythe'heat-treatment of a part 0 each object adjacent to said member. Other objects are to provide such a member which shall be adapted to serve as a link holding the objects, such as sawblades, in a chain while under longitudinal tension, but which shall be self-releasing when the ten'sion ceases, in the same manner as the link-member employed in connection with such a chain as fully explained and claimed in my said patent.

- In the accompanylng drawing illustrating one species only of the new apparatus preferably employed in my new process,

Figure 1 is a diagram section through apparatus such as shown in my said patent, illustrating one class of product and one form of apparatus only;

Fig. 2 isa side elevation of a link-member;

Fi 3 is an endclevation of said linkmem r;

Fig. 4 is a her; and

Fig. 5' illustrates abutting annealed ends perspective of said link-memof two saw-blades adapted to be temporarily joined together by said link-member.

The apparatus, referring now to Fig. 1, is

preferably such as to move a chain of the Specification of Letters Iatent' Patented May 14, 1918. f Application filed January 21, 1918. Serial No. 212,906. I

and tension will be maintained between D and F. The, oven H may be any structure cally, suflicientl ing the time 0 their progress through the .oven to the desired critical heat for the desired hardenin or temper. As shown, the objects are relatively thin steel hack-saw blades, and the time during which it 1s necessary to subject them to treatment in oven H to bring them to a tempering heat is relatively short. 'From the oven H the heated blades pass immediately, during a predetermined time, to the cooling bath B, which may be any suitable trough or tank in which the saws are showered by a stream of suitable fluid, such as oil, delivered through pi eB.

'lhe objectsvare connected, according to the present invention, by link-members 3 having a relatively considerable mass. In the preferred form shown a cast-iron or steel link is provided with lugs 11 having mwardly facing shallow notches y to take into perforations a. in the ends of two ad acent saw-blades w, the bodies of the link-members being furnished with a flange 3 adapted to protect and cover a predetermined extent of the end of a saw engaged with the lu 3 A chine or rib 3 on the opposite side 0 the link-member from the lugs 3 provides additional mass, as well as a convenient handle for manually stringing together the saws and link-members and a lateral 'de for coaction with the grooves m in t e upper rolls D and F. Each link member is preferably beveled ofl at each end at y to enable itreadily to run under the rolls.

When the chain :0, y is subjected to heat in the oven H, the ends w of the saws or other objects and the link-members 3 are heated to the annealing point, but may not reach the temperature, in their time of passage, attained by the thinner objects a: throughout the remainder of their lengths. But when the link-members 3/ pass out of the oven, and into the cooling-bath, the temperature of all of the saws except the parts m is rapidly lowered. By reason both of the greater mass of the link-members and the protection affordedthe ends of the objects m by the flanges 3 so that the oil-shower does not at the places m impinge directly on the objects :12, the annealed ends a of the obj ects cool slowly, so that when delivered they are still soft.

It will be obvious that both the objects treated and'the form .of the link-members may be varied as desired; it is apparent, for instance,'that instead of depending on perforations inthe objects and lugs on the linkmembers, this relation might be reversed, or

tively considerable mass adjacent to a predetermined portion of said objects, and progressively subjecting the chain during predetermined times first to an annealing heat and then to the action of acooling fluid, whereby to temper the objects and leave the portions adjacent to said link-members in their annealed condition. 2. The process of heat-treating metal ob- Lects comprising connecting them in a chain y temporary link-members having a relatively considerable mas adjacent to one side of a predetermined ortion of said objects, and progressively su 'ecting the chain of objects and link mem ers during predetermmed tlmes first to an annealing heat and then tothe action of a cooling fluid delivered from the cooling fluid by said link-members.

{5. A link-member adapted to join metal ob ects together in a chain during heat-treatment comprising means for engagement with the objects, and means adapted to contact with a substantial surface of the adjacent object, whereby to protect a substantial predetermined part of the member adjacent to the place of engagement of said linkmember from rapid cooling.

4. A link-member adapted to join metal objects together in a chain during heat-treat-.

ment having thereon means adapted to engage the objects and a flange projecting over and protectlng parts of said objects at and near the point of engagement of said means and object.

o. link-member adapted to join metal ob ects together in a chain during heat-treatment having therein object-engaging means, means for protecting a surface of the objects, and a rib adapted to serve as lateral guidefmeans for the chain and to increase the vmass of the link-member, whereby to delay cooling.

6. A link-member for use in tempering and annealing apparatus comprising a body havmg flanges and lugs projecting from the flanged portion adapted releasably to engage perforations in objects to-be treated, whereby to temporarily connect said objects and link-members in a chain and to protect and cover portions of the objects.

Signed by me at Springfield, Massachusetts, this 17th day of January, 1918.

CHARLES NAPIER. 

